The past two decades have witnessed important shifts in the sexual and reproductive health and behavior of U.S. youth. As children with migration backgrounds are the fastest-growing segment of the population (Tienda and Haskins 2011), the future direction of these trends increasingly will depend on nativity differentials in health and health behavior. Sexual and reproductive health and behavior during the transition to adulthood have lifelong implications for health and wellbeing, and major economic consequences as medical costs skyrocket. Despite a large body of work on the immigrant health advantage, and nativity differences in fertility, research to date on the sexual and reproductive health and behavior of immigrant youth has been limited and has stopped short of explaining observed nativity differentials. Dr. Goldberg proposes to use two nationally representative longitudinal surveys to examine nativity differences in the timing of sexual initiation and first birth and the presence of sexually transmitted infections among young men and women in the United States, and to investigate key mechanisms for nativity differentials in health. It is conceivable that recent immigrants' observed health advantage across a variety of outcomes (e.g., Cho et al. 2004; Hummer et al. 2007) reflects their source country socialization. To examine whether and how context of socialization influences observed links between nativity and youth sexual and reproductive health and behavior, Dr. Goldberg proposes to pair measures of age at immigration, an important proxy for the extent of early socialization into host country institutions and values, and region of origin. The proposed research also will investigate whether and how various types of family instability mediate observed relationships between nativity and the outcomes of interest. A major explanation for the immigrant health advantage centers on immigrant children's greater tendency than natives to live with married parents in stable unions (Perreira and Ornelas 2011; Haskins and Tienda 2011); however, family disruption and reconstitution associated with immigration, and periods of doubling up with extended kin and non-kin, may pose risks for youth with migration backgrounds (Adsera and Tienda 2012; Angel and Tienda 1982; Tienda and Angel 1982). To fulfill the proposed research plan, Dr. Goldberg requires additional substantive training in the areas of international immigration and U.S. children and families, and methodological training in topics such as survival analysis and multilevel modeling. Dr. Goldberg's team of mentors have developed a customized training plan that includes formal coursework and seminars in addition to one-on-one mentoring, which is designed to execute the proposed research plan within the planned timeframe; to extend her professional networks; to enhance her publication record; and, importantly, to produce a competitive federal grant proposal. Combined, these activities will ensure her success in obtaining an academic position at a major research university.